Next year work will fall into two categories. (1) Cockroaches: Continued analysis, using surgical, microlesioning and neuro-histological techniques of the exact location of the pacemaker in each optic lobe, and the pathways by which they (a) are mutually coupled and (b) coupled to the thoracic ganglia. Techniques will be developed for chronic recording of electrical activity of the roach brain. Micro thermodes are also being developed in a new attempt at microlocalization of the pacemaker. (2) Mice (Mus musculus C57 B1/6J): Is the pacemaker for the activity/rest rhythm located in the nucleus suprachiasmaticus (SCN) as it appears to be in some other rodents. Goals include: (a) more precise localization of the pacemaker than has been achieved in other species; (b) more extensive exploration of other parts of the hypothalamus--are they certainly not involved; (c) is there a distinct pacemaker for the body-temperature rhythm.